(1) Field of the Invention
This invention relates to agriculture, more particularly to the application of herbicides.
(2) Description of the Prior Art
The use of herbicides for control of weeds is widespread in agriculture today. Generally, pre-plant and pre-emergent herbicides may be broadcast over fields without injury to crop plants. Few herbicides, however, are specific for weeds alone and so once a crop has emerged it is necessary to treat only the weed with herbicide to avoid killing the crop plant. The problem is aggrevated in the western regions of the United States which have high temperatures, low humidity and dry winds. With the application of herbicides by a damp applicator, there is a very high evaporation rate from the applicator so that it is necessary to continually replenish the fluid supply of herbicide to the applicator.
Selective means for the dispensation of herbicides have recently come to be known. These methods of treating weeds has become increasingly important as "hoe hands", who manually kill weeds are unavailable. Also, general distribution of even pre-plant or pre-emergent herbicide stunts the growth of many crops.
Methods of selectively applying herbicides to weeds after the emergence of a crop have largely been very involved mechanically or ineffective. Heretofore, no simple method for selective application of herbicides to weeds after emergence of crops has been known in the art.
Before filing this application, applicant caused a search of the prior art to be made at the United States Patent and Trademark Office. That search revealed the following patents:
U.S. Pat. No. 1,109,060, Griffin; PA1 U.S. Pat. No. 1,523,590, Hartshorn; PA1 U.S. Pat. No. 1,764,952, Hay; PA1 U.S. Pat. No. 1,818,369, Watson; PA1 U.S. Pat. No. 2,123,988, Corley; PA1 U.S. Pat. No. 2,935,818, Crane; PA1 U.S. Pat. No. 3,021,642, Ewing; PA1 U.S. Pat. No. 3,077,701, Osmun; PA1 U.S. Pat. No. 3,320,694, Biron; PA1 U.S. Pat. No. 4,019,278, McKirdy.
Ewing discloses a solid sheet-like wick extending from the bottom of a header with a few inches of head thereon.
Hay disclosed a boll weevil poisoner having wet strands hanging from a chamber with liquid therein.
Watson shows a series of strands hanging down vertically from an axial pipe which distributes the liquid to it.
While the other patents cited are thought by applicants to be of little interest with respect to their invention, other workers in the field are continuing to work in this area. The work done using the capillary action of woven Nylon rope is progressing at the time of this application.